Wireless networks are widely known in which mobile devices communicate with base stations within range, the base stations forming “cells” and the mobile devices being handed over from one cell to another as they move around the network. Such networks, referred to below as “wireless cellular networks”, are planned and centralised, with a mobile operator responsible for their construction and maintenance.
‘Ad-hoc’ mobile networks are very different from such wireless cellular networks. Without centralised control, an ad-hoc network must assemble itself from any devices that happen to be nearby, and adapt as devices move in and out of wireless range. The building blocks of ad-hoc mobile networks are low-power devices that must do their own wireless routing, forwarding signals from other devices that would otherwise be out of radio range. As such, ad-hoc networks tend to be short-range in comparison with the longer-range wireless communication possible in wireless cellular networks.
Various wireless protocols are capable of being used for ad-hoc networking, such as WiFi, Bluetooth and ZigBee. Recently, smartphones have become available which offer such short-range wireless functionality in addition to being compliant with one or more wireless cellular network standards such as GSM, 3G, LTE or WiMAX.
Recent events such as the Tōhoku earthquake and tsunami in Japan in March 2011, have highlighted the value of mobile devices. Apart from capturing images and reporting to the world the gravity of the situation, such devices can receive warnings via the mobile operator in the forms of news, SMS, etc. Smart mobile devices with GPS and suitable applications can determine their locations and warn users of imminent threats like an oncoming tsunami or hurricane.
A major problem in any large-scale emergency is the huge demand on the mobile infrastructure resources. Everyone wants to make a call or send a message at once, leading to system overload and unavailability. However, if during such emergencies mobile devices could collaborate and organize themselves into small groups, this demand could be greatly decreased. In such groups, rather than multiple devices using the voice, SMS service or accessing the Internet at the same time, only one selected device performs these tasks on the behalf of the group.
Currently, many mobile devices are capable of wirelessly exchanging information via protocols like Bluetooth or WiFi. However, for security reasons, such access usually requires express authorization from the user. Moreover, in order to save battery or simply because of a lack of need, some of these protocols may be disabled at any given time.
There is consequently a need for a technology that, in the event of an emergency, deals with the automatic enabling and setup of such protocols and their automatic configurations for the purpose of ad-hoc networking.